Nested cup



R. J. KIECKHEFER NESTED CUP Nov. 14, 1950 Filed May 29, 1944 INVENTOZEaaerd. MECKHEFEK BY 4% MVAM ATTOKNEYS Patented Nov. 14, 1950 Robert J.K-ieckhefer, Brookfield, Wis., assignor to American-Lace Paper Company,Milwaukee, Wi's., a corporation of Wisconsin ApplicationMay 29, 1944,Serial No. 537,833

5 Claims.

This invention relates to improvements in nestedcups and cups adaptedfor nesting;

In the manufacture of cups having a bottom flush with the lower marginof thewalls and merging therewith on a gradual curve, it is found thatthe angle of. the cup wall to the vertical is only acceptablecommercially ifconfined within an extremely'narrow range of" angles.Cups of the class referred to: are made of pulp, paper, plastics, andother materials. In such cups, as heretofore made, therehas been nothingto. restrict the telescopic nesting interengagement of the cups exceptthe contact between the walls themselves. In this respect, such cups aredifferent from cups so madethat the bottom is elevated and serves to.limit the nesting engagement.

Where the nesting. engagement is limited by contact between the walls,the angularityof wall usually requiredcommercially permits the walls towedge so tightly as to make difficult the sepaa ration of the cups inthe nested stack becauseof the friction of the area of the wall surfacein nested contact. Awall angularity of such degree as will virtuallyeliminate friction between such surfaces as are in nested contactso-reduces the size of the'bottom in relation to the size of the lip asto make the cup appear awkwardand the cup is in actual fact top-heavyand easy to upset.

It is the object of. thepresent invention to provide means incorporatedexternally in the wall of the cup to prevent wedging and facilitateseparation of the cups in the stack without requiring the wall angle tobe increased beyond the range dictated by commercial considerations. Itwill be apparent that not every means of limiting the nesting movementwould be suitable. Whatever limiting means is employed must be such aswill not interfere with the withdrawal of the cup from any moldsorforming dies used in cup'manufacture, and the preferred means will notrender the cup unsightly or impair its strength, or make it difficult toclean or interfere with any operations which may subsequently beperformed upon it.

In the drawings:

Figure l'is a view partially in side elevation and partially in sectionshowing a stack of cups embodying the invention.

Figure 2 is an enlarged fragmentary detail of a lower side portion andbottom of one of the cups.

Figure 3 is a fragmentary detail view on the scale of Figure 1, showinga modified form of cup embodying my invention.

Like parts are identified by the same reference characters throughoutthe several views.

Each of the cups 3 is formed in such a manner that the major length ofits side wall 4 comprises the frustum of a cone having approximately aseven degree angle to the axis of the cone. The

2. Y bottom 5 is integral with the side walLthe-iimer surfaces mergingon abroad curve as indicated at 6. The bottom may have anupwardconvexity so as to ensure non-interference with the firm seatprovidedlby theannular: exterior surface at]. 1 r.

The particular cups herein disclosed are molded of paper pulp, but,asabove indicated; the invention is alsoapplicable tocups ofLot'hermaterials, whether molded or fabricated. The

particular advantages-of the invention are-realized when the relation ofthe bottom .to the side Wall is such that the cup bottom does notprovide a stop limiting the wedging of one cup within another.

To overcome such wed'ging, the first disclosed embodiment of the presentinvention contem-'- plates that each cup be provided at H) with acylindrical surface deviating from the general frusto-conical externalsurface of the wall 4. V

This results in thickening the wall in the'zone indicated at I0 andincreasing the radius ofthe curve at H as compared with the radius-ofthe interior curve at 6. Although the wall surface it may appear, totheeye, to'fiare outwardly in a downwardly direction, the fact is that hiscylindrical, thus making it possible to withdraw such a cup from aforming die in the usual'manner and'to conduct pressure finishingoperationsin the usual manner.

The difference in the overall radial dimensionsof' the'cupzon'e l0, II,when thecupis made in accordance with this invention, as com pared withthe corresponding dimensions of prior art cups, omitting the cylindricalsurface l0,

may be so slight as to be of the order of 6 of an inch. Yet, as clearlyshown in Figure l; the

cylindrical zone of each cup serves to space the entire remaining wallportions of each cup*approximately of andrzch-from" the wall portions ofother cups withwhich it is nested. No matter how firmly cups embodyingthis invention are stacked together in the nested form illustrated inFigure l, the slightest tilting of the changed and the thickening of thewall to the slight extent necessary to provide a cylindrical surface at[0 not only has the advantage as above described, but actually increasesthe stability and meets the other objectives specified for theinvention.

In the modified embodiment of Figure 3, the cup I3 has its wall M at thesame angle of approximately seven degrees to the axis which theexperience of the industry has found to be desirable. Its inner surfaceat 16 retains its conventional smooth and easily cleaned shape, havingneither ribs nor flutes.

Its lower external surface, instead of being fully cylindrical as in theconstruction shown in Figure 1 and Figure 2, merely approaches acylindrical outline to the extent that it is provided with ribs at 26,the apices of which extend to an imaginary cylinder. For such materialas plastics or the like this is a very satisfactory arrangement to keepthe otherwise frusto-conical wall portions of nested cups out ofcontact. Plastics are sufficiently firm and unyielding so that a fullcylindrical contour is not necessary for the 4 purpose. The less denseand more easily compressible the material of which the cup is made, themore important it may be to have the zone l approach a fully cylindricalform.

It will be understood that the ribs 26 illustrated in Figure 3 exemplifybut one possibility in the way of providing projections from theexternal base portion of each cup to space its frustoconical wallportions from the like Wall portions of other cups. Like the fullcylindrical outline shown at I0 in Figure 1, the ribs of Figure 3 havethe advantage of permitting easy withdrawal of such a cup from a formingdie or mold.

I claim;

1. A molded container having a generally frusto-conical Wall and anintegral bottom with which both the interior and exterior surfaces ofthe wallmerge curvilinearly, the said wall being provided immediatelyabove the inner surface of said bottom: with external spacing meanscomprising portions slightly thickened outwardly beyond adownward-projection of the frusto-conical external surfaceptthe-rest ofthe wall but within a; cylindrical outline V merging therewith so thatthe container may be withdrawn from a-mold, the overall diameter of saidspacing means being smaller than the interior of all portions of the cupoth'er than the extreme bottom portions thereof, wherebysaidcontainermay be nested in a like container, the said spacing means providing onlytangential contact between containers soneste'd. v

2. The container of claim 1 in which the slightly thickenedwall'portions have the form of peripherally spaced projections.

3. The container of claim 1 in which the walls are of substantiallyuniform thickness throughout a major portion of their height, deviatingfrom such substantial uniformity only where thickened. adjacent thebottom as aforesaid.

4. A molded one-piece container adapted to 4 nest compactly withidentical containers and yet to be readily freed from any tendencytoward frictional retention in nested engagement, said containercomprising a generally frusto-conical wall and integral bottom, the wallbeing generally of uniform thickness and having inner and outer surfacesat substantially uniform spacing except in a predetermined narrowperiphera1 zone in a Wall portion otherwise substantially fullyengageable with a like nested cup, one of said surfaces having a portiondeviating gradually from the other in said zone to increase the wallthickness and to vary said surface portion from frustoconical toward acylindrical form, whereby the said portion can be withdrawn from a moldand will nevertheless provide contact of the deviating surfacesubstantially in a peripheral line about a like nested cup, cups sonested being elsewhere spacedby the said thickened wall and relativelypivotable upon each other at said zone for releasing any tendency towardfrictional retention. 5. A one-piece container of molded pulp adapt: edto nest compactly With identical containers and yet to bereadily freedfrom any tendency toward frictional retention in nested engagement, saidcontainer comprising a generally frustoconical wall of substantiallyuniform thickness throughout most of its height, and a bottom integralwith the wall and having inner and outer surfaces, the said wall flaringupwardly at an angle of approximately seven degrees from its axis andbeing of substantially uniform thickness for almost all of its height, aportion of said wall having a substantially cylindrical surface in anarrow zone above the inner surface of said bottom merging smoothly withan adjacent frustoconical surface thereof, whereby said container may bedrawn from a mold and nevertheless the said cylindrical surface willprovide a substantial- 1y linear peripheral spacing contact with anidentical nestedcontainer to permit relative pivotal movement of thenested containers to free them from mutual frictional retention.

ROBERT J. KIECKHEFER.

. REFERENCES CITED The following references are of record in the file ofthis patent:' a

UNITED STATES PATENTS Number

